Dihydrophenanthrofurans and bisbibenzyl derivatives from the stems of Dendrobium nobile

Dendrocandin U from Dendrobium officinale Kimura et Migo Inhibits M1 Polarization in Alveolar Macrophage by Suppressing NF-κB Signaling Pathway

Dendrobium officinale Kimura et Migo is a valuable and homologous medicine and food traditional Chinese medicine. Currently there are few studies on the anti-inflammatory activity of lipophilic components. The aim of this study was to explore the anti-inflammatory effect and mechanism of the lipophilic compounds in Dendrobium officinale. Six compounds were isolated and identified, including three bibenzyl compounds, dendrocandin U, dendronbibisline B, erianin, and three lignans, (-)-syringaresinol, (+)-syringaresinol-O-β-D-glucopyranoside, 5-methoxy-(+)-isolariciresinol. Among them, dendronbibisline B and 5-methoxy-(+)-isolariciresinol were isolated from Dendrobium officinale for the first time. Besides, we found dendrocandin U, dendronbibisline B and (-)-syringaresinol exhibited the anti-inflammation to inhibit nitric oxide secretion induced by lipopolysaccharide (LPS)/interferon (IFN-γ) in MH-S cells. Furthermore, dendrocandin U could inhibit the expression of tumor necrosis factor-α (TNF-α), Cluster of Differentiation 86 (CD86), and reduce inflammatory morphological changes of macrophages. Meanwhile, we confirmed that the anti-inflammation mechanism of dendrocandin U was to inhibit M1 polarization by suppressing toll-like receptor 4 (TLR4)/recombinant myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) signaling pathway. In this paper, dendrocandin U with significant anti-inflammatory activity was found from Dendrobium officinale, which could provide a basis for the study of its anti-inflammatory drugs.

Complete 1 H and 13 C assignments of two new sesquiterpenoids from Dendrobium aduncum

Two new sesquiterpenoids, dendroaduoid A (1) and dendroaduol (2), together with four known sesquiterpenoids were isolated from the stems of Dendrobium aduncum. Their structures were identified by HR-ESI-MS and NMR experiments, and the complete assignments of ¹ H and ¹³ C NMR data for two new sesquiterpenoids were obtained by the aid of HSQC, HMBC, ¹ H-¹ H COSY, NOESY, and ECD techniques. The cytotoxic effects of the isolated compounds on four tumor cell lines (HCT-116, HepG2, A549, and SW1990) were evaluated using MTT assay. Otherwise, the inhibitory activity of these six sesquiterpenoids on glycosidase was also evaluated.

Recent Research Progress on Natural Stilbenes in Dendrobium Species

Dendrobium is the second biggest genus in the Orchidaceae family, and many of them have been utilized as a traditional Chinese medicine (TCM) for thousands of years in China. In the last few decades, constituents with great chemical diversity were isolated from Dendrobium, and a wide range of biological activities were detected, either for crude extracts or for pure compounds. Stilbene compound is one of the primary active constituents in the genus Dendrobium. At present, 267 stilbene compounds with clarified molecular structures have been extracted and isolated from 52 species of Dendrobium, including 124 phenanthrenes and 143 bibenzyls. At the same time, activity studies have indicated that 157 compounds have pharmaceutical activity. Among them, most of the compounds showed antitumor activity, followed by antioxidant, anti-inflammatory and anti-α-glucosidase inhibitory activities. Additionally, 54 compounds have multiple pharmacological activities, such as confusarin (14), 2,4,7-trihydroxy-9,10-dihydro-phenanthrene (43), moscatilin (148), gigantol (150) and batatasin III (151). This review summarizes current knowledge about the chemical composition of stilbene, bioactivities and pharmacologic effects in 52 species of Dendrobium. We also expect to provide a reference for further research, development and utilization of stilbene constituents in the Dendrobium genus.

Antioxidant and anti-inflammatory activity of constituents isolated from Dendrobium nobile (Lindl.)

Dendrobium nobile (Lindl.) have long been used as herbal tea and a traditional herbal medicine to treat Alzheimer’s disease (AD). In the current study, nineteen compounds (1–19), including two new vitamin E homologues (1–2), one new sesquiterpene (6), and two new dendrobines (7, 8), were isolated and identified from stems of Dendrobium nobile. Their structures were elucidated on the basis of NMR, ¹³C NMR calculation, and DP4⁺ probability analyses. The absolute configurations of new compounds were determined by electronic circular dichroism (ECD) data analysis. Antioxidant, anti-inflammatory, and cytotoxic activities of isolated compounds were evaluated. Among them, compound 2 demonstrated significant antioxidant activity compared with ascorbic acid (VC), while compounds 2 and 4 also exhibited an equal effect to positive control cisplatin. This study on the biological activity of the new vitamin E homologues from Dendrobium nobile may indicate its potential application in the pharmaceutical and food industries.

Transcriptome and Metabonomics Analysis Revealed the Molecular Mechanism of Differential Metabolite Production of Dendrobium nobile Under Different Epiphytic Patterns

The cultivation medium of Dendrobium nobile has an effect on the contents of its main medicinal components, but the specific mechanism is still unclear. In this study, the callus, seedlings, rhizomes, and leaves of D. nobile were sequenced for the PacBio SMRT. The 2-year-old stems were selected for the Illumina sequencing and metabolome sequencing to analyze the genetic mechanism of metabolic differences under different epiphytic patterns. As a result, a total of 387 differential genes were obtained, corresponding to 66 differential metabolites. Different epiphytic patterns can induce a series of metabolic changes at the metabolome and transcriptome levels of D. nobile, including flavonoid metabolism, purine metabolism, terpenoid backbone biosynthesis, amino acid metabolism, and alpha-linolenic acid metabolic, and related regulatory genes include ALDH2B7, ADC, EPSPS-1, SHKA, DHAPS-1, GES, ACS1, SAHH, ACS2, CHLP, LOX2, LOX2.3, and CYP74B2. The results showed that the genetic mechanism of D. nobile under various epiphytic patterns was different. In theory, the content of metabolites under the epiphytic patterns of Danxia stone is higher, which is more suitable for field cultivation.

Dihydrophenanthrenes and phenanthrenes from Dendrobium terminale

Two previously undescribed dihydrophenanthrene derivatives (1 and 2) were isolated along with twelve known analogues from the whole plant of Dendrobium terminale. The structures of the new compounds were elucidated on the basis of detailed spectroscopic analysis. The NMR data of known phenanthrene derivatives (7 and 9) were revised by 2D NMR. The isolated compounds were evaluated for cytotoxicity against three kinds of tumor cell lines (sw1990, HCT-116, and HepG2). Especially compounds 11 and 14 showed stronger antitumor effects, and the structure-activity relationship of these compounds was discussed.

Orchidaceae-Derived Anticancer Agents: A Review

Simple Summary

Orchids are commonly used in folk medicine for the treatment of infections and tumors but little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. According to the published data, numerous species of orchids contain potential antitumor chemicals. Still, a relatively insignificant number of species of orchids have been tested for their bioactive properties and most of those studies were on Asian taxa. Broader research, ’including American and African species, as well as the correct identification of samples, is essential for evaluating the usefulness of orchids as a plant family with huge anticancer potential.

Abstract

Species of orchids, which belong to the largest family of flowering plants, are commonly used in folk medicine for the treatment of infections and tumors. However, little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. For the assessment, previous papers on the anticancer activity of Orchidaceae published since 2015 were considered. The papers were found by exploring electronic databases. According to the available data, many species of orchids contain potential antitumor chemicals. The bioactive substances in a relatively insignificant number of orchids are identified, and most studies are on Asian taxa. Broader research on American and African species and the correct identification of samples included in the experiments are essential for evaluating the usefulness of orchids as a plant family with vast anticancer potential.

Dendrobine-type alkaloids from Dendrobium nobile

Six dendrobine-type alkaloids were isolated from the tubes of Dendrobium nobile by silica gel, Sephadex LH-20 gel column chromatography, and preparative HPLC. Compound 1 is a new alkaloid containing a pair of amide tautomers, whereas compound 2 is a new dendrobine-type alkaloid. By using spectroscopic techniques including 1 D and 2 D NMR, the structures of compounds 1‒6 were identified as N-methoxylcarbonyldendrobine (1), dendronboic acid (2), dendrobine (3), 6-hydroxyldendrobine (4), dendrobine N-oxide (5), and denrine (6). The cytotoxic effects of the isolated compounds on two human tumour cell lines (HCT-116 and SW1990) were evaluated using MTT assay.

Dihydrophenanthrenes from a Sicilian Accession of Himantoglossum robertianum (Loisel.) P. Delforge Showed Antioxidant, Antimicrobial, and Antiproliferative Activities

The peculiar aspect that emerges from the study of Orchidaceae is the presence of various molecules, which are particularly interesting for pharmaceutical chemistry due to their wide range of biological resources. The aim of our study was to investigate the properties of two dihydrophenanthrenes, isolated, for the first time, from Himantoglossum robertianum (Loisel.) P. Delforge (Orchidaceae) bulbs and roots. Chemical and spectroscopic study of the bulbs and roots of Himantoglossumrobertianum (Loisel.) P. Delforge resulted in the isolation of two known dihydrophenanthrenes-loroglossol and hircinol-never isolated from this plant species. The structures were evaluated based on ¹H-NMR, ¹³C-NMR, and two-dimensional spectra, and by comparison with the literature. These two molecules have been tested for their possible antioxidant, antimicrobial, antiproliferative, and proapoptotic activities. In particular, it has been shown that these molecules cause an increase in the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) in polymorphonuclear leukocytes (PMN); show antimicrobial activity against Escherichia coli and Staphylococcus aureus, and have anti-proliferative effects on gastric cancer cell lines, inducing apoptosis effects. Therefore, these two molecules could be considered promising candidates for pharmaceutical and nutraceutical preparations.

Isolation and characterization of neolignan derivatives with hepatoprotective and neuroprotective activities from the fruits of Citrus medica L. var. Sarcodactylis Swingle

The fruit of Citrus medica L. var. sarcodactylis Swingle is a functional food with rich nutrients and medicinal values because of its content of bioactive compounds. A bioactivity-guided chemical investigation from the fruits of C. medica L. var. sarcodactylis Swingle afforded three new benzodioxane neolignans (1-3), three new phenanthrofuran neolignan glycosides (4-6), two new biphenyl-ketone neolignans (7-8), two new 1',7'-bilignan neolignans (9-10), as well as fourteen known neolignan derivatives (11-24), which were isolated and characterized from the fruits of C. medica L. var. sarcodactylis Swingle for the first time. These neolignan derivatives were determined by extensive and comprehensive analyzing NMR, HR-ESI-MS, UV, IR spectral data and compared with the data described in the literature. Among them, compounds 1-3 and 12-13 exhibited moderate hepatoprotective activities to improve the survival rates of HepG2 cells from 46.26 ± 1.90% (APAP, 10 mM) to 67.23 ± 4.25%, 62.87 ± 4.43%, 60.06 ± 6.34%, 56.75 ± 2.30%, 58.35 ± 6.14%, respectively. Additionally, compounds 7-8 and 21-22 displayed moderate neuroprotective activities to raise the survival rates of PC12 cells from 55.30 ± 2.25% to 66.94 ± 3.37%, 70.98 ± 5.05%, 64.64 ± 1.93%, and 62.81 ± 4.11% at 10 μM, respectively. The plausible biogenetic pathway and preliminary structure-activity relationship of the selected compounds were scientifically summarized and discussed in this paper.